Search

The density, conductivity, and viscosity of the 1,3-dimethyl-2-imidazolinone and lithium nitrate (DMI– LiNO3) solvated ionic liquid were measured as a function of temperature. Additionally, the electrochemical mechanism and electrodeposition of neodymium from the DMI–LiNO3 solvated ionic liquid were investigated. Cyclic voltammetry results indicate that the electrochemical reduction of Nd(III) is irreversible and proceeds via one-step with three-electron transfer, which is controlled by diffusion with a diffusion coefficient of 5.08×10−8 cm2/s. Energy- dispersive X-ray spectrometry and X-ray photoelectron spectroscopy data confirm that the electrodeposit obtained after electrodeposition at −4 V (vs Ag) using the DMI–LiNO3–Nd(CF3SO3)3 solvated ionic liquid contains metallic neodymium.

The separation of C2 H2 from C2 H4 is one of the most challenging tasks due to the similarity of their physical properties. In addition, green synthetic protocol and adsorbent's stability are also the major concerns during the separation. Herein, under hydrothermal green synthesis conditions, an ultrastable ultramicroporous Zn-MOF was designed and synthesized with a high yield. The pore diameter of the Zn-MOF is 3.6 A, which lies in between the diameters of C2 H2 (3.3 A) and C2 H4 (4.2 A) molecules, leading to an efficient separation of the C2 H2 /C2 H4 mixtures by the sieving effect. The practical separation performance of C2 H2 /C2 H4 was confirmed by the dynamic breakthrough experiments. Moreover, the high stability enables the adsorption capacity of the Zn-MOF to C2 H2 , which can be maintained under a wide range of pH (1-13). Molecular simulations were also performed to identify the different C2 H2 - and C2 H4 -binding sites in Zn-MOF.

Objective The aim of this study was to determine the clinical outcomes and long-term stability of individualized titanium mesh combined with free flap for orbital floor reconstruction after maxillectomy and to identify the risk factors for titanium mesh exposure. Material and methods The data of 66 patients who underwent maxillectomy and orbital floor defect reconstruction by individualized titanium mesh in Peking University School and Hospital of Stomatology between 2011 and 2019 were retrospectively reviewed. Postoperative ophthalmic function and success of aesthetic restoration were assessed. Titanium mesh exposure was recorded and the risk factors were identified. Results Mean follow-up was for 24.8 months (range, 6-92 months). Ophthalmic function was successfully restored in 63/66 patients. Aesthetic restoration was not considered satisfactory by 10 patients. Titanium mesh exposure occurred in six patients (exposure rate, 9.1%). Preoperative radiotherapy was identified as an independent risk factor for mesh exposure (OR = 28.8, P = 0.006). Previous surgery, postoperative radiotherapy, pathological type of the primary lesion, the type of tissue flap applied, and the use of intraoperative navigation were not significant risk factors. Six patients with titanium mesh exposure underwent second surgery, but mesh exposure recurred in two patients due to insufficient soft tissue coverage. Conclusion Individualized titanium mesh with free flap can effectively restore maxilla-orbital defects. Preoperative radiotherapy is an independent predictor of postoperative titanium mesh exposure. Adequate soft tissue coverage of the mesh may reduce the risk of mesh exposure. Level of evidence Level 4 (case-control study) Laryngoscope, 2021.

The two functional fluorinated ligands 2-fluoro-4-(1H-tetrazol-5-yl)benzoic acid (2-F-H2tzba) and 3-fluoro-4-(1H-tetrazol-5-yl)benzoic acid (3-F-H2tzba) were obtained by modifying 4-(1H-tetrazol-5-...

On the basis of an undeveloped asymmetrical pyridylcarboxylate ligand, 2-(2-carboxypyridin-4-yl)terephthalic acid (H3CPTA), an indium pyridylcarboxylate framework, [(Me)2NH2]1.5[In1.5(CPTA)2]·5.5NMF·6H2O (1), is synthesized under solvent thermal conditions. 1 displays a 3D anionic framework with a large void space, which contains open square channels with a cross section of 14.6 A and a pore surface decorated with carboxylic oxygen atoms. Depending on the anionic skeleton and high water stability, 1 exhibits high adsorption selectivity and capacity for cationic dyes in aqueous solution. Furthermore, the luminescence performance illustrates that 1 has selectivity and sensitivity to nitenpyram with good recyclability.

In this paper, gas sensing characteristics of Boron-doped graphene oxide(B-GO) are presented firstly. In order to detect the optimal value of boron doping, different amounts of boron (5-30 wt%) are adopt in the doping process. The results of sensing test revealed that at room temperature (20 °C) and humidity (30%), 15 wt% B-GO has the optimal sensitivity to NH3. Meanwhile, the detection response and recovery time of B-GO gas sensor to NH3 are relatively short. Theoretical models of graphene and B-doped graphene are established, and energy change in the gas-adsorption of NH3 on the graphene oxide or B-doped graphene oxide is calculated. The enhanced sensing performance was ascribed to the B-doping and the formation of chemical bonds between boron and NH3.

Owing to perovskite possessing the outstanding optoelectronic properties, perovskite-based solar cells show prominent performance. The stability of perovskite-based solar cells hampers the progress of commercialization, so it is important to understand the microstructure mechanism of perovskite degradation under the humidity and oxygen environmental conditions. In this study, a meaningful Debye-type dielectric relaxation was observed under water vapor and oxygen co-treatment conditions. Interestingly, the relaxation was not observed under water vapor or oxygen treatment individually. This new dielectric relaxation is identified as a direct result of dipole jump, and its activation energy was measured to be 630 ± 6 meV. According to photoelectron spectroscopy and 13C nuclear magnetic resonance data, we suggest that the dipoles are formed by CH3NH3+ (MA+) and superoxide (O2-), which originate from the distorted crystal lattice and water vapor-weakened hydrogen bonds of Pb-I cages. In addition, the activation energy fitted by dielectric relaxation might be the energy of ion migration. This study contributes to understanding the mechanism of perovskite degradation from the view of microstructure relaxation and evolution, and also provides a method for the analysis of ion migration energy.

The efficient backbone-directed self-assembly of cyclic metalla[3]catenanes by the combination of tetrachloroperylenediimide (TCPDI)-based dinuclear rhodium(III) clips and 4,4'-diazopyridine or 4,4'-dipyridylethylene ligands is realized in a single-step strategy. The topology and coordination geometry of the cyclic metalla[3]catenanes are characterized by NMR spectroscopy, ESI-TOF-MS spectrometry, UV/Vis-NIR spectroscopy, and X-ray diffraction studies. The most remarkable feature of the formed cyclic metalla[3]catenane is that it contains π-aggregates (ca. 2.6 nm) incorporating six TCPDIs. Further studies revealed that cyclic metalla[3]catenanes can be converted reversibly to their corresponding sodium adducts and precursor building blocks, respectively. This strategy opens the possibility of generating unique supramolecular structures from discrete functional π-aggregates with precise arrangements.

Electrochemical carbon dioxide reduction meditated by metallic catalysts suffers from restricted selectivity and competition from hydrogen evolution, which sensitively depends on ambiguous contributions of alloying and strain state in bimetallic catalysts. Herein, nanoporous Au-Sn (NPAS) containing trace tin solute in Au lattices is delicately designed to convince real strain effect, while eliminating other undesirable factors, such as alloying, crystal facets and surface composition. Compared with nanoporous gold (NPG), the NPAS with a solute strain of ∼2.2 % enables more efficient CO2-to−CO conversion, with an efficiency as high as 92 % at -0.85 V versus reversible hydrogen electrode (vs. RHE), and the high activity can retain for more than 8 h. The combination of HRTEM and surface valence band photoemission spectra reveals that the tensile strain on the surface of 3D nanoporous structure promotes the catalytic activity by shifting up the d-band center and strengthening the adsorption of key intermediate *COOH. A small amount of Sn solute in the nanoporous alloy can prevent ligament coarsening effectively and improve the electrochemical stability.

Based on the mixed carboxylate ligands synthesis strategy, an indium-organic framework, (Me2NH2)1.5[In1.5(FBDC)(BDC)]·2.5NMF·CH3CN (1) has been constructed by using the mixed (2,5-di(2',5'-dicarboxylphenyl)-difluorobenzene (H4FBDC) and terephthalic acid (H2BDC). Compound 1 contains a 3D intersecting pore system which surface is modified by F atoms, and it has excellent stability in pH = 2-12 aqueous solutions. The activated 1 shows high separation for C2H2/CO2 and C2H2/CH4. Moreover, 1 not only has strong luminescence but also has the high selectivity and sensibility of fluorescence detection to nitrofurazone (NZF) in antibiotic sensing experiments, which can be used as a luminescence sensor for NZF detection.

The explosion pressure and minimum explosible concentration (MEC) properties of metal sulfide ore dust clouds are valuable for the prevention and control of metal sulfide ore dust explosions. In this study, a 20 L explosion sphere vessel was used to investigate the effect of sulfur content, particle size, and concentration on the explosion pressure and minimum explosible concentration of metal sulfide ore dust clouds. Four samples with different sulfur contents were selected (30%–40%, 20%–30%, 10%–20%, and 0%–10%). Before and after the explosion, samples were tested by X-ray diffraction. The results indicate that the metal sulfide ore dust is explosive dust with St1 grade explosion pressure. With an increase in concentration, the maximum explosion pressure increased at first and then decreased. With an increase in sulfide content, the explosion pressure of metal sulfide ore dust increased, while the minimum explosible concentration decreased. As particle size decreased, the MEC also decreased. The sulfur content, particle size, and concentration of metal sulfide ore dust were the main factors affecting the explosion hazard.

Palladium-catalyzed alkene-directed cross-coupling of aryl iodide with another aryl halide through C-H arylation opens a unique avenue for unsymmetrical biaryl-derived molecules. However, homo-coupling of aryl iodides often erodes the overall synthetic efficiency. Reported herein is a highly chemoselective Pd0 -catalyzed alkyne-directed cross-coupling of aryl iodides with bromophenols, which was subsequently followed by phenol dearomatization to furnish a very attractive [2+2+1] spiroannulation. Notably, possible homo-coupling of aryl iodides was not observed at all. Mechanistic studies indicated that a five-membered aryl/vinyl palladacycle most likely accounts for promoting the key step of biaryl cross-coupling.

Carbon dioxide electroreduction provides a useful source of carbon monoxide, but comparatively few catalysts could be sustained at current densities of industry level. Herein, we construct a high-yield, flexible and self-supported single-atom nickel-decorated porous carbon membrane catalyst. This membrane possesses interconnected nanofibers and hierarchical pores, affording abundant effective nickel single atoms that participate in carbon dioxide reduction. Moreover, the excellent mechanical strength and well-distributed nickel atoms of this membrane combines gas-diffusion and catalyst layers into one architecture. This integrated membrane could be directly used as a gas diffusion electrode to establish an extremely stable three-phase interface for high-performance carbon dioxide electroreduction, producing carbon monoxide with a 308.4 mA cm−2 partial current density and 88% Faradaic efficiency for up to 120 h. We hope this work will provide guidance for the design and application of carbon dioxide electro-catalysts at the potential industrial scale., Here the authors deploy Ni single atom-decorated carbon membranes as integrated gas diffusion electrodes to construct an extremely stable three-phase interface for CO2 electroreduction, producing CO with a partial current density of 308.4 mA cm–2 and a Faradaic efficiency of 88% for up to 120 h.

The first isolable Ge5-spiropentadiene 1 was synthesized via the reduction of (iPr3Si)2NGeCl (3) with potassium. The crystal structure of 1 reveals a spirocyclic Ge5 skeleton containing two Ge-Ge double bonds (avg. 2.34 A), which are fettered in two Ge3 rings with a dihedral angle of 70.193°. The DFT calculations and orbital analysis show that the σ-delocalization of the Ge5 skeleton and the 2π-delocalized aromatic Ge3 rings enhance the stability of molecule 1.

In this paper, gas sensing characteristics of sulfur-doped graphene oxide (S-GO) are firstly presented. The results of the sensing test revealed that, at room temperature (20 °C), S-GO has the optimal sensitivity to NH3. The S-GO gas sensor has a relatively short response and recovery time for the NH3 detection. Further, the sensing limit of ammonia at room temperature is 0.5 ppm. Theoretical models of graphene and S-doped graphene are established, and electrical properties of the graphene and S-doped graphene are calculated. The enhanced sensing performance was ascribed to the electrical properties’ improvement after the graphene was S-doped.

The new indium-based organic framework {(Me2NH2)[In(BDPO)]·DMF·2H2O}n (1) was successfully constructed by using the oxalamide group modified ligand N,N'-bis(isophthalic acid)oxalamide (H4BDPO). This framework presents a 2-fold interpenetrating structural characteristic, and the unique polar pore environment leads to a high capture ability for CO2, C2Hn and CH3OH and good separation ability for CO2 and C2Hn over CH4 as well as for CH3OH over C2H5OH, which was further verified by an ideal adsorbed solution theory (IAST) calculation. Theoretical simulations pointed out the possible adsorption sites of different adsorbed gases in 1. In addition, the excellent chemical stability and strong luminescence of 1 give it an effective selective detection ability for 2,6-dichloro-4-nitroaniline (DCN) in water with a low detection limit of 3.85 ppm, and the detection mechanism is discussed in detail.

Vegetables are an ideal source of human Se intake; it is important to understand selenium (Se) speciation in plants due to the distinct biological functions of selenocompounds. In this hydroponic study, the accumulation and assimilation of selenite and selenate in pak choi (Brassica rapa), a vastly consumed vegetable, were investigated at 1-168 h with HPLC speciation and RNA-sequencing. The results showed that the Se content in shoots and Se translocation factors with selenate addition were at least 10.81 and 11.62 times, respectively, higher than those with selenite addition. Selenite and selenate up-regulated the expression of SULT1;1 and PHT1;2 in roots by over 240% and 400%, respectively. Selenite addition always led to higher proportions of seleno-amino acids, while SeO42- was dominant under selenate addition (>49% of all Se species in shoots). However, in roots, SeO42- proportions declined substantially by 51% with a significant increase of selenomethionine proportions (63%) from 1 to 168 h. Moreover, with enhanced transcript of methionine gamma-lyase (60% of up-regulation compared to the control) plus high levels of methylselenium in shoots (approximately 70% of all Se species), almost 40% of Se was lost during the exposure under the selenite treatment. This work provides evidence that pak choi can rapidly transform selenite to methylselenium, and it is promising to use the plant for Se biofortification.

All-inorganic CsPbX3 (X = Cl, Br, and I) nanocrystals (NCs) are emerging as attractive semiconductor materials because of their outstanding optical properties. The low resistance of CsPbX3 NCs to light, heat, oxygen, and water has been recognized as a major obstacle to their practical applications. Here, we demonstrate that the stability of CsPbX3 NC films can be dramatically enhanced by Ar plasma treatment. It is revealed that plasma irradiation can induce ligand polymerization in the NC films if the ligands contain unsaturated carbon bonds. The ligand polymerization leads to encapsulation of the NCs in the ligand polymers. Because of the precise localization of the in situ ligand polymerization under plasma irradiation and the high NC content in the films without extra additives, the polymerized area can be precisely defined down to several micrometers. This enables easy fabrication of high-resolution NC pixels for next generation displays.

Purpose Zygomatic complex defects after extensive maxillectomy can cause severe esthetic and functional deformities. Patient-specific titanium mesh fabricated using a computer-assisted technique is a promising method for such midface reconstruction. The aim of this study was to evaluate the application and clinical outcomes of this technique. Patients and Methods This was a retrospective study that included 9 patients with zygomatic complex defects after extensive maxillectomy from 2015 through 2017 at the authors' institution. A 3-dimensional stereo model was obtained based on mirror images of the unaffected side to fabricate a patient-specific titanium mesh using computer-assisted design and manufacturing. Titanium mesh was used to restore the contour of the zygomatic complex with free flap reconstruction after tumor resection. Anterolateral thigh flaps were used in 8 cases and a myocutaneous fibula flap was used in 1 case. Symmetry of the zygomatic complex was evaluated by measuring the zygomatic eminence on the postoperative computed tomogram, and complications were recorded during follow-up visits. Facial symmetry was self-evaluated and scored. Results Mean duration for follow-up was 27.3 months (range, 15 to 39 months). Mean deviation of the zygomatic eminence between the reconstructed and unaffected sides was 1.4 ± 0.5 mm. No significant difference was noted in the zygomatic eminence between the reconstructed and unaffected sides (P = .591). Titanium mesh exposure occurred in only 1 patient after radiotherapy. There were no other remarkable complications. All patients were satisfied with their postoperative facial symmetry. Conclusion Patient-specific titanium mesh fabricated using a computer-assisted technique was an alternative option for extensive zygomatic complex reconstruction, resulting in acceptable clinical outcomes. A study with a larger sample and long-term follow-up is needed for the observation of long-term outcomes and risk of titanium mesh-related complications.

To construct desired metal–organic framework (MOF) sensors, the predesigned functionalized ligands 2,5-bis(2′,5′-dicarboxylphenyl)pyridine (L-N) and 2,5-bis(2′,5′-dicarboxylphenyl)difluorobenzene (...

Sodium-ion batteries (SIBs) have received great attention due to the low cost and abundance of sodium resources, and their chemical/electrochemical properties are similar to those of established lithium-ion batteries. In the past few years, we have witnessed the resuscitation and rapid development of various advanced electrode materials. Rationally designed nanostructures endow the electrodes with high reversible capacity, superior rate capability, and long-term cyclability. In this Review, we summarize some recent research progress in the rational design and synthesis of nanostructured electrode materials with controlled shape, structural complexity, composition, and boosted sodium storage performance. We seek to provide some understanding on the effect of nanostructure engineering on the sodium storage properties of electrode materials. It is thus anticipated that this Review will shed some light on the development of high-performance electrode materials for advanced SIBs.

Se can regulate Cd accumulation and translocation in plants; however, such effects can be controversial because of the differences in plant species and Se species. In this study, pak choi was cultured under hydroponic conditions, and the effects of selenite and selenate on Cd accumulation were investigated in the edible parts of this vegetable. The results showed gradual improvements in the effects of the two Se species on the Cd content in pak choi shoots at the four assessed growing stages. Selenite did not lead to significant changes in Cd accumulation in the shoots until day 40, when it significantly reduced the accumulation by 34%. Selenate was always found to increase the Cd content in the shoots, and the differences on days 19 and 40 were 16% and 45%, respectively, compared with those of the Cd (only) treatment. Accordingly, selenate invariably enhanced Cd translocation from the roots to the shoots, whereas selenite insignificantly reduced the translocation only on day 40. Generally, selenomethionine (SeMet) accounted for much larger proportions in selenite-treated plants, while SeO42− was the dominant Se species in selenate-treated plants. However, under both Se treatments, the SeMet proportion increased substantially from day 19 to day 40 when that of SeO42− exhibited a drastic decrease; therefore, the relative proportion of seleno-amino acids to SeO42− may be the key factor for the regulation of Cd accumulation in pak choi via treatment with selenite and selenate at the different growing stages.

Metal sulfides with excellent redox reversibility and high capacity are very promising electrode materials for sodium-ion batteries. However, their practical application is still hindered by the poor rate capability and limited cycle life. Herein, a template-based strategy is developed to synthesize nitrogen-doped carbon-coated Cu9 S5 bullet-like hollow particles starting from bullet-like ZnO particles. With the structural and compositional advantages, these unique nitrogen-doped carbon-coated Cu9 S5 bullet-like hollow particles manifest excellent sodium storage properties with superior rate capability and ultra-stable cycling performance.

To synthesize novel polynuclear lanthanide single-molecule magnets, a tetranuclear dysprosium compound, namely [Dy4(L)4(OH)2(DMF)2(TMAA)2] •2 (CH3CN) (H2L = 2-(2-Hydroxy-3-methoxybenzylideneamino)phenol, HTMAA = trimethylacetic acid, DMF = dimethylformamide, and CH3CN = acetonitrile), was synthesized, structurally and magnetically characterized. The key structural feature of this compound is that four Dy(III) ions are nearly coplanar in a regular parallelogram, forming a distorted defective dicubane {Dy4O8} core. Furthermore, this compound shows Single Molecule Magnets (SMMs) behaviour with a high energy barrier of 56 K among tetranuclear Dy(III) SMMs.

An interpenetrated indium pyridylcarboxylate framework, [NH2(CH3)2][In(L)2]·2.5DMF·5H2O (1), has been synthesized by employing a pyridylcarboxylate ligand, 4-(3-carboxylphenyl)picolinic acid (H2L), and an In3+ ion, with both chemical stability and framework flexibility. The desolvated 1 exhibits an uncommon breathing sorption behavior and shows highly selective adsorption for C2H2, C2H4, and CO2 over CH4. Furthermore, 1 shows rapid and higher adsorption efficiency for methylene blue and neutral red in aqueous solution.

In this work, the carbon-based microsphere with hollow-nanoflower structure was designed and applied to the targeted drug delivery system (TDDS) in order to improve drug loading and microwave control efficiency. We utilize the “silicon-assisted” method to tailor the hollow mesoporous carbon nanoflower (HMCNF) microspheres as base material, then small Fe3O4 particles (5–12 nm) were precipitated on the HMCNF by thermal decomposition and modified with SiO2 to obtain Fe3O4/HMCNF-SiO2 composites. The tailor-made Fe3O4/HMCNF-SiO2 has unique hollow “flower-dewdrops” structure, large BET surface area (292.21 m2/g) and uniform pore size (5.61 nm) to achieve large storage of drugs. Meanwhile, the Fe3O4/HMCNF-SiO2 has the appropriate magnetic properties (Ms = 8.91 emu/g) and good microwave heat transfer performance, which can achieve the drug carrier targeting and microwave-triggered release. Furthermore, the Fe3O4/HMCNF-SiO2 has a higher drug loading rate of 70.20% (DOX loading of 175.50 mg/g) and an expected release behavior. It maintains a very low drug release rate only 1.5% at pH = 7.4 and then increased to 25.2% after microwave stimulation at pH = 5.0. Therefore the Fe3O4/HMCNF-SiO2 composite nanocarrier is expected to widely use in microwave-triggered drug delivery system.

A novel palladium-catalyzed [4+1] spiroannulation was developed by using a C(sp3 )-H activation/naphthol dearomatization approach. This bimolecular domino reaction of two aryl halides was realized through a sequence of cyclometallation-facilitated C(sp3 )-H activation, biaryl cross-coupling, and naphthol dearomatization, thus rendering the rapid assembly of a new class of spirocyclic molecules in good yields with broad functional-group tolerance. Preliminary mechanistic studies indicate that C-H cleavage is likely involved in the rate-determining step, and a five-membered palladacycle was identified as the key intermediate for the intermolecular coupling.

To better understand the factors determining the multi-step relaxation processes in polynuclear lanthanide single molecule magnets (SMMs), two Dy(iii)4 SMMs showing two-step relaxation processes were elaborately designed and investigated for their structure-dependent magnetic properties. Through targetedly fine-tuning the auxiliary ligand (from the anion of 1-phenylbutane-1,3-dione to 2-acetylcyclopentanone) on specific Dy(iii) sites while retaining the same type of coordination atoms, one of the two relaxation processes shifted to higher temperature with an increase of energy barrier, which permits the unambiguous assignment of the relaxation processes to specific metal sites. Therefore, the present {Dy4} systems provide a good example to probe the factors determining the relaxation dynamics, and point to a simple way to optimize the magnetic performance of polynuclear dysprosium SMMs.

Due to their high theoretical specific capacity, CoSe2-based anode materials have attracted enormous attention for sodium storage. However, the poor cycling stability and rate capability still hinder their application. Herein, starting from Co3[Co(CN)6]2 Prussian blue analogue microcubes, a facile template-engaged strategy is developed to design and synthesize nanostructured dual-carbon-confined CoSe2 (denoted as DCC-CoSe2) microcubes. In this unique nanostructure, N-doped carbon-coated CoSe2 nanoparticles are confined in N-doped carbon microboxes. Benefiting from the desired structural features, the as-synthesized DCC-CoSe2 microcubes exhibit enhanced sodium storage properties in terms of high specific capacity (480 mA h g−1), excellent cycling stability (94.5% capacity retention over 2000 cycles), and superior rate capability (281 mA h g−1 at 20 A g−1). The assembled full cell with DCC-CoSe2 microcubes as the anode material and Na3V2(PO4)3 as the cathode material can deliver a high initial capacity of 427 mA h g−1. This work provides a new strategy for the rational design and synthesis of high performance metal selenide-based anode materials for sodium storage.

The five new Ni(II) coordination polymers (CPs) {[Ni(bitp)(bpe)0.5(H2O)2]·0.5bpe}n (1), {[Ni(bitp)(bpa)0.5(H2O)2]·0.5bpa}n (2), {[Ni(bitp)(4,4′-bpy)0.5(H2O)]·H2O}n (3), {[Ni1.5(bitp)(Hbitp)(2,2′-bp...

By employing a pyridyl-decorated dicarboxylic acid ligand, 3-(2′,5′-dicarboxylphenyl)pyridine acid (H2dcpy), a three-dimensional In3+-based metal–organic framework, H3O[In3(dcpy)4(OH)2]·3DMF·4H2O (1), with a good chemical stability toward acid and base has been synthesized. The compound 1 shows an uncommon (3,8)-connected tfz-d; UO3 topological net based on linear In3(COO)4(OH)2 clusters and also contains one-dimensional open channels. Particularly, 1 contains two types of dcpy2– linkers, in which the pyridyl group in one participates in coordination with the In3+ ion, whereas that in the other is uncoordinated but hangs in the inner sides of the channels as functionalized sites. Gas adsorption experiments demonstrate that 1 is able to selectively adsorb C2H2, C2H4, and CO2 over CH4. Simultaneously, 1 shows a highly selective and sensitive fluorescence detection toward Fe3+ ion in water with good recyclability.

Carbon emissions cost is a potential effective measure to restrict hydrocarbon pollution in the international shipping trade. The minimization of the total cost is pursued by ship operators, whereas voyage cost is increasingly involving the replacement of clean fuel and changing the cost of the shipping route. A flexible optimization method focusing on maximizing the total profit is developed in terms of sailing speed optimization and single port skips integrate carbon emission influence. An actual ocean shipping route from Shanghai to Rotterdam is applied to validate the effectiveness of the proposed models. The results have shown that the shipping route profit is volatile along with the sailing speed and the number of port calls. However, the profit will be maximized when applying the single port skip and will slow down the sailing speed at the same time. The demand of planned skip port can be supported by a short line container. A system composed of ocean container liner and short line container can improve the profit by 4.05% and reduce the carbon emission by 19.70%. Furthermore, sensitive results show that the profit is less affected by the changing of the carbon emission cost. A small size container has enough ability to solve the short transportation demand in adjacent ports and convert extraberthing cost into profit. These findings can provide reliable support for the shipping route decision process considering future carbon emission costs.

Replacing sluggish oxygen evolution reaction (OER) by hydrazine oxidation reaction (HzOR) is an energy-saving approach to assist alkaline overall water splitting (OWS). However, it is still at the infant stage as the unsatisfactory of the design strategies for bifunctional catalysts toward both HzOR and hydrogen evolution, which leads to high working potential compared to the theoretical value. Here, for the first time, we report a galvanostatic immobilization of ruthenium single atoms (Ru SAs) into the oxygen vacancy of urchin-like tungsten trioxide (Vo-WO3) and show low overpotentials of 17, 34, and 64 mV at –10 mA cm–2 under acid, alkaline, and neutral H2 evolution, respectively. As an efficient bifunctional catalyst, the Vo-WO3/Ru SAs is firstly introduced to HzOR and achieves low working potential of –58 mV at 10 mA cm–2. The HzOR-assisted OWS also delivers an ultralow cell voltage of only 25 mV at 10 mA cm–2 in alkaline medium, which is far beyond the platinum and most of the state-of-the-art catalysts. Additionally, this coupled system can also be well performed under neutral condition, realizing a cell voltage of only 137 mV at 10 mA cm–2. The excellent pH-universal HzOR-assisted OWS activity is attributed to the particular electronic configuration between Ru SAs and WO3, the immobilization of Ru SAs in WO3 could induce electron redistribution and optimize free energy of hydrogen adsorption in hydrogen evolution, while the isolation of Ru SAs also leads to the electropositivity of W sites and tends to accelerate the oxidation of hydrazine.

Selenite and phosphate share similar uptake mechanisms, as a phosphate transporter is involved in the selenite uptake process. However, the mechanism by which selenium (Se) transformation in plants is mediated by phosphorus (P) remains unclear. In this hydroponic study, the absorption, translocation, and biotransformation of Se in selenite-treated rice (Oryza sativa L.) seedlings were investigated under varying P nutrient status. The results showed that P-deficient cultivation increased the Se concentration in roots with Se-only treatment by 2.1 times relative to that of the P-normal condition. However, co-treating roots with additional P caused the Se concentration to decline by 20 and 73% compared to Se treatment alone under P-normal and P-deficient cultivation, respectively. A similar pattern was also observed in Se uptake by rice roots. With an Se-transfer factor elevated by 4.4 times, the shoot Se concentration was increased by 44% with additional P supply compared to the concentration under Se-only treatment of P deficiency; however, no significant differences were observed regarding P-normal cultivation. P deficiency increased the Se percentage by 28% within the cell wall, but reduced it by 60% in the soluble fraction of Se-only treated roots relative to that of the P-normal condition. Contrarily, compared with the Se-only treatment under P deficiency, additional P supply enhanced Se storage in the root soluble fraction by 1.3 times. The opposite tendency was observed for rice shoots. Moreover, P deficiency reduced the proportion of SeMet by 22%, but increased MeSeCys by 1.3 times in Se-only treated roots compared to those under the P-normal condition. Interestingly, MeSeCys was not detected when additional P was added to the two cultivation conditions. Unlike in the roots, only SeMet was generally detected in the rice shoots. The results demonstrate that the P nutrient status strongly affects the Se biofortification efficiency in rice seedlings by altering the Se subcellular distribution and speciation.

The properties of supramolecular structures are highly dependent on their metal-centered building blocks and organic linkers, thus the search for novel systems will lead to new functions and applications for these unique assemblies. Here, two discrete triangular trimetallic sandwich building blocks were developed to construct supramolecular assemblies through coordination-driven self-assembly with organosulfur ligands. A series of tubelike (Tr2Pd3)4L6 assemblies (Tr = cycloheptatrienyl ring) were obtained from a discrete triangular tripalladium sandwich complex with bifunctional organosulfur ligands. By replacing the metal centers of the platinum analogue, the self-assembly process resulted in the clean formation of (Tr2Pt3)2L3 triple helicates instead of tubelike species. The trimetallic sandwich building blocks were also shown to form face-capped (Tr2M3)4L4 (M = Pd or Pt) tetrahedral cages when trifunctional organosulfur ligands were used. The supramolecular assemblies were comprehensively analyzed by X-ray crystallography. A metal-cluster-induced structural transformation between (Tr2Pd3)4L4 tubes and (Tr2Pt3)2L3 triple helicates was observed. Furthermore, the face-capped (Tr2Pd3)4L4 cage possesses a tetrahedral cavity allowing the encapsulation of a series of guests.

In this work, rich oxygen vacancies are obtained in Co9S8@NiCo-LDH core-shell nanotube arrays (NTAs), which boost its electrochemical energy storage performance. The flexible carbon cloth (CC) supported Co9S8@NiCo-LDH NTAs are synthesized by situ growth and electrodeposition method. After reacting with NaBH4, the rich oxygen vacancies are generated in NiCo-LDH nanosheets to obtain Co9S8@oxygen vacancies-NiCo-LDH NTAs (Co9S8@OV-NiCo-LDH NTAs). These oxygen vacancies increase the charge transfer rate in the multi-level redox processes and make the electrochemical performance improve sharply. At a current density of 0.5 A g−1, the mass specific capacity of Co9S8@OV-NiCo-LDH NTAs is up to 1335 C g−1, which is more than four times higher than that of the untreated Co9S8@NiCo-LDH NTAs. In addition, with the prepared Co9S8@OV-NiCo-LDH core-shell NTAs as a positive electrode, along with the negative electrode of activated carbon (AC), a high-performance flexible all-solid battery-capacitor hybrid supercapacitors (HSC) device is assembled. The maximum energy density is up to 101.1 Wh kg−1 when the power density is 800 W kg−1.

To comparably analyze the influence of a porous environment on the gas adsorption in MOFs, based on an imidazole-decorated MOF, {[Zn(imtp)]·DMA·1.5H2O}n (1-im, H2imtp = 2-(imidazol-1-yl) terephthalic acid), an analogue MOF, {[Zn(tztp)]·DMA}n (1-tz, H2tztp = 2-(1H-1,2,4-triazol-1-yl) terephthalic acid) has been synthesized by replacing imidazole with triazole motifs. The two MOFs are isostructural frameworks containing 1D channels; however, they possess different porous wall environments. The open nitrogen-decorated channels in 1-tz lead to significantly enhanced C2H6 (76.5 cm3 g–1) and C2H4 (73.1 cm3 g–1) uptakes at 298 K and 1 atm, which are 5 times of the adsorption amounts of C2H6 and C2H4 in 1-im that is the absence of exposed N atoms in the channels. Furthermore, the activated 1-tz also reveals higher adsorption selectivities for C2H6 and C2H4 over CH4. The different sorption properties were further uncovered by theoretical simulations.

Cadmium (Cd) in rice grains is a potential threat to human health. This study investigated the effects of selenite fertilisation (0 mg kg−1, 0.5 mg kg−1, and 1.0 mg kg−1) on soil solution Cd dynamics and rice uptake. Rice was grown in two Cd-contaminated soils in Jiangxi and Hunan Provinces under two different sets of conditions: aerobic and flooded. The experiments were conducted in pots. The plants were harvested at the seedling stage and at maturity to determine their Cd levels. Soil solutions were also extracted during the growing season to monitor Cd dynamics. The results showed that in the Jiangxi soil (pH 5.25), Cd concentrations in the soil solutions, seedlings, and mature rice plants were higher under aerobic than under flooded water management conditions. In the Hunan soil (pH 7.26), however, flooding decreased Cd levels in the rice seedlings but not in mature plants. Selenite additions to the Hunan soil decreased Cd concentrations in the soil solutions and in the mature rice plants. These effects were not observed for the solutions or the plants from Jiangxi soil amended with selenite. Relative to the control treatment, 0.5 mg kg−1 selenite decreased the rice grain Cd content by 45.2% and 67.7% under aerobic and flooding conditions, respectively. The results demonstrated that water management regimes affected rice Cd uptake more effectively in Jiangxi than in Hunan soil, whereas selenite addition was more effective in Hunan than in Jiangxi soil. Selenite addition was also more effective at reducing rice grain Cd levels when it was applied under flooding than under aerobic conditions.

In order to investigate the interaction between double spherical tungsten fragments and Composition B (Comp B) covered by tantalum coverplates, the numerical simulation was carried out by using AUTODYN-3D software. The influence on the shock initiation characteristics of double fragments at various distance separation b1, time separation h1, impact angle α with the same or different velocities were analyzed, and the critical initiation velocity of covered Comp B was obtained. The obtained simulation results show that, under certain circumstances, the superposition effect of shock waves caused by double fragments impact on covered Comp B is obvious. The critical initiation velocity increases with the increase of b1 when fragments impacting on covered charge at the same time with same or different velocities, with α=0, and approaches critical velocity of a single fragment. The critical initiation velocity decreases initially and then increases with the increase of h1 when fragments impacting asynchronously on covered charge with different velocities and α=0. When fragments impacting synchronously on covered Comp B with different velocities, the critical velocity decreases initially and then increases with the increase of α. When fragments impacting asynchronously on covered Comp B with different velocities, the critical velocity increases with the increase of h1. Therefore, a shock initiation of covered Comp B rather be achieved by multiple fragments at lower velocity than by a single fragment at higher.

The accumulation of arsenic (As) in rice grain is a potential threat to human health. Our study investigated the possible mediatory role of selenite fertilization on As uptake and accumulation by rice (Oryza sativa L.) under different water management regimes (aerobic or flooded) in a pot experiment. Soil solutions were also extracted during the growing season to monitor As dynamics. Results showed that As contents in the soil solutions, seedlings, and mature rice were higher under flooded than under aerobic water management. Under aerobic conditions, selenite additions slightly increased As concentrations in soil solutions (in the last two samplings), but decreased As levels in rice plants. Relative to the control, 0.5 mg kg−1 selenite decreased rice grain As by 27.5%. Under flooded conditions, however, selenite additions decreased As in soil solutions, while increased As in rice grain. Tendencies also showed that selenite additions decreased the proportion of As in rice shoots both at the seedling stage and maturity, and were more effective in aerobic soil. Our results demonstrate that the effect of selenite fertilizer on As accumulation by rice is related to water management.

Using a triazole carboxylic ligand (H2L = 4-(1H-1,2,4-triazol-1-yl) isophthalic acid), four water-stable lanthanide metal–organic frameworks (Ln(III)-MOFs) (1-Ln, Ln(III) = Tb, Eu, Dy, and Sm), [Ln...

A novel solid sodium-ion conductor, Na2Mg2TeO6 (NMTO) with a P2-type honeycomb-layered structure, has been synthesized for the first time by a simple solid-state synthetic route. The conductor of NMTO exhibits high conductivity of 2.3 × 10-4 S cm-1 at room temperature (RT) and a large electrochemical window of ∼4.2 V (versus Na+/Na). The conductor is remarkably stable, both in the ambient environment and within its metallic Na anode. This facile sodium-ion conductor displays potential for use in all-solid-state sodium-ion batteries (SS-SIBs).

Summary Tin disulfide (SnS 2 ) is a promising anode material for sodium-ion batteries because of its high specific capacity. However, the low conductivity and large volume change during reaction with Na + ions greatly limit its practical application. Herein, a multistep templating method has been exploited for the rational design and synthesis of SnS 2 nanosheets confined in carbon nanotubes (SnS 2 @CNTs). To demonstrate the universality of this method, SnS 2 nanosheets confined in carbon nanoboxes (SnS 2 @CNBs) and hollow carbon nanospheres (SnS 2 @CNSs) have also been synthesized by simply changing the template in the reaction system. Due to their unique structural merits, the SnS 2 @CNTs, SnS 2 @CNBs, and SnS 2 @CNSs show improved sodium storage performance in terms of high specific capacity, good cycling stability, and superior rate capability.

This paper presents an investigation on the energy absorption behavior of shrink circular tube under quasi-static loading by experimental and numerical methods. The circular tube is shrunken in radial direction under axial compression by a cone bush. Energy is absorbed by the plastic bending/compression of tube and the friction between tube and cone bush. Quasi-static crushing tests on aluminum alloy circular tubes demonstrate the feasibility of this type of energy absorber. Numerical simulations are performed to investigate tube deformations and driving force – stroke responses, which agree well with experimental results. On the basis of validated numerical model, effects of friction coefficient, cone angle, and tube dimension on driving force response and energy absorption efficiency are investigated by numerical simulations. It is observed that the shape of driving force – stroke curve is significantly affected by cone angle and tube dimension, whereas it is almost not affected by friction coefficient. Friction energy is almost linearly dependent on friction coefficient, and plastic energy almost linearly increases with an increase in cone angle. In addition, the compact tube has a higher energy absorption efficiency. A comparison on the maximum specific energy absorptions of shrink circular tube and expansion circular tube, reveals that shrink circular tube has a higher energy absorption efficiency.

To explore a diverse number of energy absorption methods, this paper presents an investigation of a cutting aluminium tube absorber for railway vehicles. A quasi-static cutting experiment on an aluminium tube is conducted. The finite element models presented in this study are based on experimental tests, and good agreement is achieved between the experimental and finite element results. It is shown that the cutting aluminium tube absorber presents a stable deformation mode. The chip morphologies of the numerical simulation and experimental test results are coincident, demonstrating that failure criteria defined under the material model are effective. Moreover, a parametric study is performed using finite element models under quasi-static loading. It is found that the cutting depth t, cutting depth w and cutting angle α have a distinct effect on the energy absorption (EA), mean crushing force (MCF) and peak crushing force (PCF) of the absorber. Sobol’ sensitivity analysis is employed to analyze the effects of the design parameters (t, w, and α) on the objective responses (EA and PCF) based on a polynomial response surface model. It is found that at a larger cutting depth, the increases in EA and PCF are larger. Additionally, to optimize the crushing performance of the absorber, a multi-objective optimization is applied to achieve the maximum EA and minimum PCF values. The results show that EA increases with increasing PCF and at the optimal point B (EA = 78.29 kJ, PCF = 341.88 kN), and thus, a balance between EA and PCF is obtained.

Arsenic (As) disrupts the biological functions of plants by inhibiting their developmental process. Selenium (Se) is a beneficial plant micronutrient when it is administered at the optimal doses. The present study investigated the possible mediatory role of selenite (Se(IV)) or selenate (Se(VI)) in arsenite (As(III)) or arsenate (As(V)) uptake by rice seedlings (Oryza sativa L.). Simultaneous exposure of rice seedlings to As(III) (5 µM) and Se(IV) (5 µM) increased the root As content after ≥30 h. The maximum increase in root As level (42.2%) was measured after 150 h. At the same time, the shoot As level decreased by 46.4% as the root-to-shoot As translocation rate declined. In contrast, Se(VI) supplementation caused the As content to decrease by 48.8% and 16.1% after 150 h in the roots and shoots, respectively. Nevertheless, when the As exposure duration was

Despite the ultrahigh energy density of rechargeable lithium–oxygen (Li-O2) batteries, their practical use is still hindered by the poor performance of electrocatalysts. Recently, porous and hollow nanostructured catalysts have been found to be promising electrocatalysts toward the ORR/OER to improve the performance of Li-O2 batteries. However, the catalytic activities of the catalysts are still insufficient and the nanopores are easily clogged by the insoluble discharge products. Herein, highly porous and hollow TiO2–x nanoboxes (TiO2–x NBs) with large surface areas, increased oxygen vacancies, and high grain boundary density have been developed as an electrocatalyst for Li-O2 batteries via a cation-assisted synthetic approach. The Li-O2 batteries with TiO2–x NBs as the electrocatalyst exhibit a high specific capacity of 8569 mA h g–1, excellent rate capability, and long cycle life up to 200 cycles when the capacity is limited to 1000 mA h g–1. Moreover, this cation-assisted approach for fine-tuning the ...